The present invention relates to building automation systems. In particular, a wireless building control architecture implements automation of building systems.
Building automation systems include heating, ventilation and air conditioning (HVAC) systems, security systems, fire systems, or other systems. The systems are typically formed from distributed components wired together. HVAC systems may be formed with up to three separate tiers or architectural levels. A floor level network provides general control for a particular floor or zone of a building. Controllers of the floor level network provide process controls based on sensor inputs to operate actuators. For example, a temperature sensor is read. An adjustment of a damper, heating element, cooling element or other actuator is determined by a separate controller based on a set point and the measured temperature. Other basic control functions for room comfort may be provided, such as by using single input, single output feedback loops employing proportional-integral-derivative methods. The building level network integrates multiple floor level networks to provide consistent control between various zones within a building. Panels or other controllers control distribution systems, such as pumps, fans or other central plants for cooling and heating. Building level controllers may communicate among themselves and also access floor level controllers for obtaining data. The management level network integrates control of the building level networks to provide a high level control process of the overall building environment and equipment. The controllers, such as a personal computer, provide supervisory and management of the building automation system. Single or dual level architectures may also be provided.
Wired building automation systems have substantial installation costs. Controllers on a floor level network are bound through installed wiring between sensors and actuators. In addition to the cost of installing wiring between the various devices, the maintenance and establishment of a network hierarchy also introduces additional cost. Further wiring connects floor level controllers to building level controllers and building level controllers to management level controllers. Further wiring adds additional costs and complication for networking. If a device within the system fails, the physical location of the device is determined manually, such as by following wiring runs from a controller reporting failure to a failed component. Manual maintenance may be expensive. Changes to the system may require additional wiring or rerouting of wiring, adding further costs.
To reduce costs associated with wiring, wireless architectures for building automation systems have been proposed. Wireless standards provide single tier networks or multiple tier networks for implementing a single building automation process. For example, a multi-tier wireless network emulates current wired building automation systems. A controller wirelessly communicates with sensors and associated actuators. The lower level sensors and actuators provide mere input and output functions controlled by controllers. As another example, a hub and spoke control in proposed in U.S. patent application Ser. No. 10/672,527 titled “Building Control System using Integrated MEMS Devices”, the disclosure of which is incorporated herein. A controller may be integrated with an actuator, a sensor or combinations thereof. An additional layer or tier uses wireless communications for management of local functions as well as management of building wide subsystems, such as chiller or building fan.
IEEE 802.15.4 standardizes wireless integrated building automation systems. Reduced function devices (RFD) with limited processing power communicate with full function devices. Full function devices (FFD) provide pier-to-pier wireless communication for controlling other reduced function devices. The standard contemplates a hub and spoke configuration between an RFD and associated FEDs while using peer-to-peer communication between FFDs.